武宁陆相红盆沉积特征与演化浅析

本文依据1:5万区调资料,扼要介绍了武宁陆相红盆填图单位的拟定、表示方法及工作原理的应用,重点叙述了红盆内多个冲积扇体特征及其之间的叠覆关系,阐明了盆缘断裂是控制红盆成生、发展演化的主导因素。对红盆成生及演化、时代也作了初步探讨。     

Foliation fields and 3D cartography in geology: Principles of a method based on potential interpolation

A modeling method that takes into account known points on a geological interface and plane orientation data such as stratification or foliation planes is described and tested. The orientations data do not necessarily belong to one of the interfaces but are assumed to sample the main anisotropy of a geological formation as in current geological situations. The problem is to determine the surfaces which pass through the known points on interfaces and which are compatible with the orientation data. The method is based on the interpolation of a scalar field defined in the space the gradient in which is orthogonal to the orientations, given that some points have the same but unknown scalar value (points of the same interface), and that scalar gradient is known on the other points (foliations). The modeled interfaces are represented as isovalues of the interpolated field. Preliminary two-dimensional tests carried-out with different covariance models demonstrate the validity of the method, which is easily transposable in three dimensions.     

Numerical modeling of 3-D terrain effect on MT field

Using the boundary element method, the numerical modeling problem of three-dimensional terrain effect on magnetotelluric (MT) field is solved. This modeling technique can be run on PC in the case of adopting special net division. The result of modeling test for 2-D terrain by this modeling technique is basically coincident with that by 2-D modeling technique, but there is a great difference between the results of 3-D and 2-D modeling for 3-D terrain. Project supported by the National Natural Science Foundation of China.     

不同岩溶动力系统的碳稳定同位素和地球化学特征及其意义——以我国几个典型岩溶地区为例

结合水化学的野外观测及室内计算,作者对桂林岩溶试验场、四川黄龙风景区和贵州乌江渡坝区3个岩溶动力系统的碳稳定同位素特征进行了分析,进而对系统的性质、系统中CO_2的来源、碳酸盐沉积过程中的碳同位素动力分馏、水化学和钙华的成因及热水钙华的~(14)C测年等地球化学问题作了探讨。结果表明,桂林岩溶试验场属于表层岩溶作用动力系统,其中的侵蚀动力主要来源于大气降水溶解土壤中的CO_2;四川黄龙风景区属于深部岩溶动力系统,侵蚀动力来自大气降水溶解幔源的CO_2;贵州乌江渡坝区岩溶系统,虽然属于表层岩溶动力系统,但其中一部分的同位素和水化学特征已受到人类活动的重大影响。     

Separate Analysis of Remote Sensing Information of Structures of Different Geological Periods and Quantitative Study of Corresponding Tectonic Stress Fields

The structural feature shown on a remote sensing image is a synthetic result ofcombination of the deformations produced during the entire geological history of an area.Therefore, the respective tectonic stress field of each of the different stages in the complexdeformation of an area can be reconstructed in three steps: (1) geological structures formed atdifferent times are distinguished in remote sensing image interpretation; (2) structuraldeformation fields at different stages are determined by analyzing relationships betweenmicrostructures (joints and fractures) and the related structures (folds and faults); and (3)tectonic stress fields at different stages are respectively recovered through a study of the featuresof structural deformation fields in different periods. Circular structures and related circlular and radial joints are correlated in space to con-cealed structural rises. The authors propose a new method for establishing a natural model ofthe concealed structural rises and calculating the tectonic stress field by using quantitative dataof the remote sensing information of circular structures and related linear structures.     

郑州国际会展中心展厅钢屋盖的动力特性分析

郑州国际会展中心展览厅钢屋盖采用了空间斜拉式索拱结构体系，为探讨该体系的动力特性，采用ANSYS有限元程序，分别建立钢屋盖与下部混凝土结构共同作用、钢屋盖单独作用以及无斜拉系统的钢屋盖单独作用时的3个空间计算模型，采用子空间迭代法计算其自振周期和振型，并加以比较。从而得出钢屋盖的动力特性，为进一步研究此类结构的受力特性奠定了基础。     

带"人字"支撑的新型复合结构体系动力特征研究

探讨了一种新型复合结构——带“人字”支撑的梁柱体系的动力特征问题。在满足静力荷载作用下承载力要求的基础上，根据结构动力学原理，推导了该结构体系的动力特征方程，分析了复合结构体系的支撑截面和型式的变化对动力特征的影响，计算显示，增加支撑对提高结构的频率即抗侧刚度有明显作用，且随支撑截面尺寸增大，固有频率单调增加。支撑倾角在一定范围内变化时，对频率影响较大，而超过该范围时，其影响明显减小，由此说明“人字”支撑为较合理的支撑型式。结果表明，所研究的具有“人字”支撑的复合结构体系具有较高的抗侧能力。     

结构动力模型试验相似理论及其验证

通过几何比尺为2的两个有机玻璃模型的结构动力试验，验证了结构动力模型试验的弹性相似律和弹性力一重力相似律。得到了以下结论：(1)大小模型频率符合相似律，一阶频率误差为2．7％、4．1％，二阶频率误差为O、6．05％。弹性相似律比弹性力一重力相似律更适合于频率预测的试验。(2)大小模型的加速度、应变符合相似律，弹性相似律的加速度误差为-1．55％～8．75％，应变误差为O．377％～7．297％。弹性力-重力相似律的加速度误差为3．07％～4．158％，应变误差为6．849％～12．959％。(3)不同相似律大小模型的时问比尺吻合很好。加速度与应变时程曲线的波形一致，既无漏峰也无错峰。     

中国中西部地区地震的重新定位和三维地壳速度结构

采用中国中西部地区(21~36N， 98~112E)193个地震台在1992～1999年间记录到的9 988次地震的Pg和Sg震相走时的读数资料，用Roecker的SPHYPIT90程序，反演了该地区三维地壳P波速度结构，并用SPHREL3D90程序进行了地震的重新定位．反演结果揭示了中国中西部地区地震P波速度结构明显的横向不均匀性，这些不同深度上波速的横向变化多以该地区的活动断裂为分界线．可以看出活动断裂两侧存在明显的速度反差．通过重新定位，得到了6 459次地震的震源参数，这些精确定位的地震震中明显沿该区活动断裂呈现条带状分布，其范围和尺度清晰地表示了这一地区地震活动与活动断裂的紧密关系．其中，82％重新精确定位的事件的震源深度在20 km以内. 这一结果与笔者用双差地震定位法得到的重新定位的震源深度分布相一致．      

新疆及边邻地区7级以上地震前后北天山地下流体动态的异常变化

重点分析了新疆及边邻地区1980年以来6次7级以上地震前后北天山地下流体动态异常资料，其中3次地震前地下水有短期前兆异常变化，震时同震地震波效应普遍存在，震后异常十分突出且幅度大；以水位为主的水动力学效应反映了大区域应力调整过程具有不可逆特征。水文地球化学参数的变化不敏感。讨论了地下水远程效应与井震距离的关系以及阶跃异常的幅度等问题。